The present invention relates generally to apparatus for servicing refrigeration systems, and more particularly to a novel portable apparatus for use in selectively recovering, recycling, recharging and/or flushing refrigerant from a refrigeration system without releasing the refrigerant to atmosphere.
It has been a common practice in servicing air conditioning and refrigeration systems, collectively termed refrigeration systems, such as employed in private and commercial vehicles and buildings, to vent to atmosphere refrigerant removed from the systems preparatory to servicing. With the increasing concern for environmental safety, it is no longer an accepted practice to vent or discharge refrigerant, such as refrigerants commercially available under the trademark "Freon", into the atmosphere due to their deleterious affect on the ozone layer. While refrigerants have been developed which are less toxic and less detrimental to the environment, legislation has been enacted in most jurisdictions which prohibits release of any refrigerants into the atmosphere. In an attempt to comply with this mandate, numerous attempts have been made to provide refrigerant processing or servicing apparatus which do not allow escape of refrigerant into the atmosphere.
In addition to environmental concerns, it is desirable that any apparatus employed to service air conditioning or refrigeration systems in vehicles and buildings be portable to enable easy transport of the refrigeration system processing apparatus to a job site. In the case of automobile or other vehicle air conditioning systems, it is highly desirable that the refrigerant processing apparatus be capable of selectively performing a number of different functions or combinations of functions, such as recycling of the refrigerant to remove oil, moisture, acids, foreign particles, and non-compressible gas in the form of air; recovery of the refrigerant wherein the refrigerant is removed from the vehicle system and passed to a storage reservoir to enable servicing and repair of the vehicle air conditioning system; recharging wherein refrigerant is removed from the vehicle system by vacuum and combined with additional refrigerant for return to the vehicle system; and flushing during which clean liquid refrigerant is charged into the high pressure side of the system while simultaneously recovering refrigerant from the low pressure side for removal of dirty oil and other contaminants from the refrigerant that might result from failure of the system compressor.
Currently used refrigerant recovery apparatus employ a number of discrete components, such as an accumulator, compressor, filter, vacuum pump, condenser, and associated valves and sensors, which are interconnected by appropriate piping for conveying the refrigerant to and from the various components. Assembly of the various components and associated piping during manufacture is labor intensive and prone to leaking and other quality control problems, thereby adding significantly to the total manufacturing cost. Moreover, the addition of a component, such as a hand valve, solenoid or check valve, to known refrigerant recovery apparatus generally entails adding at least one support bracket and extra piping and fittings, thereby leading to even greater cost and higher likelihood for failure.
It is known in refrigerant recovery apparatus to use some regenerative heat transfer, e.g. passing the high pressure refrigerant outlet pipe from the compressor through the accumulator so as to utilize heat in the compressed refrigerant for assisting evaporation of refrigerant entering the accumulator. This generally requires additional piping and a specially constructed accumulator with a heat recovery coil provided therein. Presently used refrigerant recovery apparatus also utilize a separate compressor and vacuum pump which adds significantly to the cost of the apparatus.
A further shortcoming of known refrigerant recovery apparatus relates to the possibility of incorrect operation of the apparatus. For example, where controls can be manually operated and the sequence of operations can be manually manipulated by an operator, an untrained or careless operator can operate the various controls, such as valves and switchable components, in an incorrect or inappropriate sequence leading to possible damage to the recovery apparatus and to the external system from which the refrigerant is being recovered. Risk of operator injury and release of refrigerant to atmosphere are also increased.
A general object of the present invention is to provide a novel and improved method and apparatus for recovering refrigerant from a refrigeration system.
A more particular object of the present invention is to provide a novel method and apparatus for selective recovery, recycling, recharging and/or flushing of refrigerant from a refrigeration system wherein a major portion of any selected operating phase is carried out automatically with minimal exercise of discretionary operator control.
Another object of the present invention is to provide a novel apparatus for selective recovery, recycling, recharging and/or flushing of refrigerant from a refrigeration system, wherein the apparatus is embodied in a mobile unit and includes a generally unitary compact housing defining an internal accumulator chamber, a condenser chamber, high pressure and low pressure filter chambers, and a storage chamber which are adapted for selective fluid communication through a flow channel and control valve arrangement which eliminates the relative complex tubing and valving arrangements characteristic of prior refrigerant recovery, recycling and recharging systems.
Still another object of the present invention is to provide a novel refrigerant recovery apparatus in which a single compressor/vacuum means functions as both compression means during recovery and as vacuum means during evacuation of an external system prior to recharging.
A feature of the refrigerant recycling, recovery and recharging apparatus of the invention lies in the provision of a programmed controller which precludes operation of the apparatus in a deleterious manner through minimizing incorrect or undesirable operation of the components or the sequence of operation.